The present invention relates to mechanisms for typewriters that utilize printing ribbon cartridges in general and include those of the type disclosed in U.S. Pat. No. 3,643,777 entitled TYPEWRITER RIBBON CARTRIDGE granted Feb. 22, 1972 and U.S. Pat. application Ser. No. 150,946 filed June 9, 1971 with Carl Anderson et al as inventors and entitled TYPEWRITER RIBBON CARTRIDGE, both of which are assigned to the assignee of the instant application.
The present application also represents an improvement over a simultaneously filed application entitled AUTOMATIC FUNCTION MECHANISM FOR TYPEWRITERS with Edwin Hurley as inventor in that the present application teaches the actuation of a backspace function upon insertion and removal of a cartridge and does not require the disabling of the escapement.
The term "cartridge" as used hereinafter is defined to include any form of ribbon holder or container irrespective of configuration and the manner of insertion into the typewriter.
One particularly useful typewriter function that may be accomplished by the actuating mechanism of this invention is to provide an automatic backspace operation upon insertion of a cartridge and another automatic backspace operation upon removal of the cartridge. A typical backspace operation that may be automated by the actuating mechanism of this invention is fully disclosed in U.S. Pat. No. 3,482,671 entitled BACKSPACE MECHANISM FOR TYPEWRITERS granted on Dec. 9, 1969 with Richard Shattuck as inventor and assigned to the same assignee as the instant application. When cooperating with a modified cartridge housing an error correction tape therein, manual backspacing steps necessary for error correction are directly eliminated.
The term "typewriter function" is defined to include any typewriter operation which provides for the alignment of a selected platen impact point relative to the typewriter print point.
Error correction devices for typewriters as disclosed in the prior art, have required a series of sequential manual operations of the typewriter. For example, when an operator typed an erroneous character, it was first necessary to depress the backspace key to actuate the backspace mechanism thereby repositioning the typewriter carriage to the proper printing station for making the correction. The typist would then manually position a section of correction tape over the printing station and overstrike the erroneously typed character to cover the error with correction material. Another backspace operation would then be necessary to again reposition the typewriter carriage to the proper printing station so that the correct letter may be typed over the correction material. Therefore, a series of manipulative operations by the operator are necessary to correct each erroneously typed character. The end result of the foregoing is that the typing speed is significantly reduced relative to the amount of erroneous characters typed, thereby significantly increasing the time and the cost required for the preparation of typed material.
Furthermore, the operator would inherently waste substantial amounts of correction ribbon. It is necessary to hold the correction ribbon or strip with the fingers to properly position and continuously hold the correction ribbon at the printing station until the erroneously typed character is re-struck and correction material deposited to the writing paper. The remaining portion of the correction ribbon could be unsuitable for further use, due to the correction material being rubbed from the surface of the ribbon by contact with the fingers. Consequently, a greater segment of correction ribbon might be required to correct one erroneously typed character.
The present invention overcomes the foregoing disadvantages while conserving correction material and providing an automatic spacing operation upon insertion and removal of a ribbon cartridge. With the wide distribution and use of photo copying machines, it has been customary to make only a ribbon copy and thereafter reproduce additional copies. Thus, there is no necessity to correct any multiple carbon copies.
Other advantages of the present invention will become more fully apparent from the following description.